Subject: Jumbo jet nosedive: Walkman to blame?

    "It all started with a rumor that was soon widely reported as 
    fact: a DC-10, on final approach to New York's JFK airport, 
    suddenly pitched violently to the left and nearly crashed. As 
    the story goes, the loss of control was caused by a first-class
    passenger who had turned on his portable CD player."

>From _Airlines and the Electronic Device Furor: Just Where's the
Interference?_ by investigative journalist Peter S. Greenberg in the
Sunday, April 4 edition of the San Jose (California) Mercury News, 
page 1T. He continues:

    "'That story is nothing but a rumor,' says Anthony Broderick, 
    associate administrator for regulation and certification at the
    FAA [Federal Aviation Administration - C.H.]."

    "'We've checked every available source, and that event never 
    happened,' he says. 'The picture painted in the mind's eye of the 
    public is inaccurate. We've looked at electronic emissions for 
    years, and the odds are so remote that something like this ever
    happened that we don't consider Walkmen, CD players or laptop
    computers a serious safety issue.'"

    "Specifically, Broderick explains that electronic flight controls
    are designed to be subjected to high levels of extraneous 
    electronic emissions. 'In a worst-case scenario,' he says, 'there
    are failure modes built into these systems so that if there was a
    problem, the system would either shut down or there would be an 
    alarm...in our tests we subject aircraft equipment to 
    substantially more severe electronic interference than could ever
    be caused by passive individual devices.'"

Greenberg's article also mentions a 1988 study conducted by the Radio
Technical Commission for Aeronautics, which is described as a non-
profit group that acts a a federal advisory committee. Greenberg says
the group's study reported that there was was not sufficient evidence
to prove that any of the following devices generated enough 
interference to disturb aircraft equipment: AM/FM/casette players, 
Dictaphones, hand-held video games, heart monitor units, portable 
computers, high-frequency marine band radios, and cellular phones.

As a former private pilot, I have dealt with the FAA. In my 
experience, they have ALWAYS considered aircraft safety to be their 
top priority. And after millions and millions of airline operations 
upon which to base an opinion, and after specific testing for 
interference by consumer electronics equipment, the FAA appears to
find no reason for concern.

In my opinion, it does seem logical to wonder if a radio might 
interfere with navigation receivers. After all, radios contain local 
oscillators that can emit RF. In reality, though, the already tiny 
(and unmodulated) signal  -- inside of a metal shield (the plane's
fuselage) -- drops off to a truly miniscule level inversely
proportional to the distance.

Personal computers are probably the devices most likely to cause
interference, as they can emit a relatively large amount of broadband 
RF (radio frequency noise). However, laptop computers have been used
on airline flights for several years now, and, to my knowledge, there
has been no evidence to suggest a problem.

-Craig Haggart, KC6VHO
 Stanford Synchrotron Radiation Lab at SLAC
 Menlo Park, California

        [Crossposting to alt.folklore.science and .urban,
                 and donning the asbestos suit.]


From unknown Fri May 28 01:30:14 1993
From: lippard@skyblu.ccit.arizona.edu (James J. Lippard)